1) Field of the Invention
The subject invention relates to a resonating device for attenuating sound waves that are generated by a pneumatic surgical instrument during surgery.
2) Description of the Related Art
Various resonating devices for attenuating sound waves are well known in the art. Commonly referred to as Helmholtz resonators, resonating devices are characterized by a container of fluid, usually air, with an open hole. The fluid can generally be any gas. The resonating devices often include a neck extending from the container. The neck defines the open hole at an end of the neck that is distal from the container. The most common example of a resonating device is an empty pop bottle. The resonating effect is illustrated as a person blows air across the open hole of the bottle to produce a sound.
Resonating devices operate on the well known principle of the Helmholtz equation, as set forth below:   F  =            C              2        ⁢        Π              ⁢                  A                  V          ⁢                                           ⁢          L                    
where F is a frequency produced by the resonator and is a constant with respect to the dimensions of the resonating device, C is a velocity of sound at a given temperature, A is a cross-sectional area of the open hole, V is a volume of the container, and L is a length of the hole. The equation is most easily illustrated by blowing across the top of a pop bottle, i.e. the container. By adding liquid into the bottle, which decreases the volume of the bottle, a change in sound tone can be observed resulting from the decrease in volume of the bottle.
Although resonating devices are used to produce sound, as in the aforementioned example, resonating devices are also used to eliminate sound. Resonating devices are often connected to a flow of fluid. The flow of fluid has loud sound waves traveling through it. As the flow of fluid travels through the resonating device, the fluid causes the resonating device to produce sound waves that attenuate sound waves at the same frequency traveling through the flow of fluid.
Resonating devices are widely used in automobile exhaust applications for attenuating sound waves generated by an engine. The resonating devices are generally connected to an exhaust line. Exhaust gas from the engine passes across the open hole of the resonating devices and produces sound waves. The sound waves produced by the resonating devices attenuate the sound waves produced by the engine.
Prior art resonating devices generally include a housing having an inlet, outlet, and a duct connecting the inlet to the outlet. One or more containers are generally contained within the housing and connect to the duct. The containers generally define a cavity with a neck connecting the cavity to the duct. Although multiple containers of different sizes are often used to attenuate sound waves at multiple frequencies, the prior art merely positions the containers randomly, according to space constraints, but does not suggest ordering the resonators to increase sound attenuation efficiency.
The prior art resonating devices fail to suggest extending and suspending the full neck into the volume of the container. The prior art also fails to suggest separating the neck from the container of the resonator. The prior art resonating devices require special manufacturing to achieve the dimensions required to attenuate sound waves at a specific frequency and cannot be constructed with pre-existing parts.
Furthermore, prior art resonating devices have not been applied to surgical instrument arts. Operating rooms in which surgical instruments are employed are generally small and congested. The operating rooms, when in use, are filled with surgical instruments needed for surgery. Many people often fill the operating rooms as well, including doctors and nurses, not to mention the patient. Therefore, a premium is placed upon surgical instruments that are minimal in size without compromising performance. In addition, resonating devices are required to eliminate the sound waves produced by the surgical instruments, which inhibit communication and concentration within the operating room. As a result of size constraints, the resonating devices of the prior art are too large and bulky and are therefore not practical for application to surgical arts.
Thus, there remains an opportunity for a resonating device for use in the surgical arts which is compact yet can be easily manufactured with pre-existing parts to attenuate sound waves with greater efficiency than existing resonating devices.